Exposure to bright light – similar to daylight – boosts levels of the male hormone testosterone and can triple sexual satisfaction, the research found.

“Before treatment, both groups averaged a sexual satisfaction score of around two out of 10, but after treatment the group exposed to the bright light was scoring sexual satisfaction scores of around 6.3 – a more than three-fold increase on the scale we used. In contrast, the control group only showed an average score of around 2.7 after treatment.”

While average blood levels of testosterone in the “control” group remained at around 2.3 nanograms per millilitre (ng/ml) before and after the study, those of the men receiving active light treatment rose from 2.1 ng/ml to 3.6 ng/ml.

“The increased levels of testosterone explain the greater reported sexual satisfaction,” said Prof Fagiolini. “In the northern hemisphere, the body’s testosterone production naturally declines from November through April, and then rises steadily through the spring and summer with a peak in October. You see the effect of this in reproductive rates, with the month of June showing the highest rate of conception. The use of the light box really mimics what nature does.”

And best of all, you don’t need a fancy “light box”! Just go outside and bare some skin to that giant ball of fire in the sky that God helpfully provided — for free! The study quoted above indicates that as little as 30 minutes per day in the sun will have an effect, so go get some exercise.